DHH vs. Fowler
draconianoverlord.com
draconianoverlord.com
I have neither the time nor will to refute this with actual numbers, but I can say that 1) by their nature large projects are 'in the minority' and 2) anecdotally I really doubt at this stage Rails is proportionally all that different than other frameworks.
This was probably a true statement a few years ago but there are numerous examples of large teams working on large Rails codebases at present. I'm here to tell you my day-to-day is anything but simple or small. Discovering the numerous examples of other large Rails codebases currently in production I leave as an exercise for the reader.